Select Code to Download

# %b is a hash already containing the values from fileB, with the 
# first column as keys and the second column as values.
...
  }
  print $file_of_misses "$line\n";          # no, so print it to the n
+on-match file
}

while( my $line = <$fileA> ){
   # do stuff with $line
...
while( <$fileA> ){
  my $line = $_;
  # do stuff with $line